1. Field of the Invention
The present invention relates to a method and apparatus for installing pipe and control line in a well. More specifically, the present invention relates to a method and apparatus for installing control lines secured to a string of pipe as the pipe is being made up and run into a well.
2. Background of the Related Art
Oil and gas wells may be equipped with control lines for electrically, hydraulically or optically linking various downhole devices to the surface. Control lines may be used to receive data from downhole instruments and to selectively operate from the surface downhole devices such as valves, switches, sensors, relays or other devices. One use of control lines is to open, close or adjust downhole valves in order to selectively produce or isolate formations at locations deep in the well. A control line may transmit downhole data to the surface and communicate commands to the same or other downhole devices. The control line may comprise conductive wires or cables for electrically controlling downhole devices, fibers for optically controlling downhole devices, or small-diameter tubing for hydraulically controlling downhole devices. Control lines are generally of a small diameter relative to the diameter of the pipe string to which they are secured, and are generally between 0.5 and 6 cm. in diameter. Control lines are generally secured along the length of the outer surface of a pipe string, generally parallel to the center axis of the bore of the pipe string. Continuous control lines are secured to the pipe string and installed in the well as joints of metal pipe are made up into a pipe string and run into a well. Control lines secured to pipe string are subject to being damaged and useless if pinched or crushed, by pipe slips used to grip and support the pipe string while it is being made up and run into the well.
The spider is a device used on a drilling or workover rig for gripping and supporting the pipe string as joints of pipe are made up into the pipe string. The spider has an interior bore, generally aligned with the pipe string, through which the pipe string passes. The spider has a circumferential arrangement of radially inwardly movable pipe slips disposed around the pipe string and within the internal bore. The pipe slips move radially inwardly to circumferentially grip the outer surface of the pipe string and support the pipe string in the well when the pipe string is not supported by the elevator. It is important that the pipe slips in the spider uniformly engage and grip the pipe string in order to prevent crushing or damaging the pipe making up the pipe string. Each pipe slip within the internal bore of the spider applies a force radially inwardly against the outer surface of the pipe string. It is important that the pipe slips are concave in order to contact the pipe over as large an interval as possible in order to minimize the localized stress imposed on the pipe by the pipe slips.
If a control line becomes pinched or trapped between the pipe slips of the spider and the outer surface of the pipe string, or if a control line is pinched between adjacent segments of the pipe slips as they move radially inwardly to contact the pipe string, the control line may be damaged and surface control of downhole devices may be lost or impaired. It is important that the method used to secure control lines to the pipe string be designed to prevent control line damage.
One method of installing continuous control lines as the pipe string is made up and run into the well requires that the control lines extend along the portion of the pipe string where the pipe string is held in the internal bore of the spider. A control line is circumferentially positioned along the length of the outer surface of the pipe string to coincide with a gap or recess formed in the radially outwardly disposed portion of the pipe slips and sized to accommodate the control line. This method is satisfactory for a single control line or for multiple control lines that are flexible and pliable enough to be bundled together using an arrangement of positioning arms and control line guides to redirect control lines to the desired generally parallel configuration to be received within the gap or recess. However, this method is unsatisfactory for applications requiring multiple control lines being unspooled and fed from more than one location adjacent to the spider where the control lines are more stiff or otherwise resistant to being redirected and positioned using positioning arms and guides. Also, the gap or recess formed in the radially outwardly disposed portion of the pipe slips is of limited size and is insufficient to accommodate multiple control lines required for controlling multiple downhole devices.
In many installations, it is desirable to secure multiple control lines along the length of the outer surface of the pipe string in order to allow surface control of multiple downhole devices. Multiple control lines are especially useful in deep offshore wells that penetrate multiple formations. Existing designs may require four or more control lines for each string of pipe that is run into the well. Multiple control lines are most efficiently made, stored, transported and installed in bundles comprising control lines coupled together in a generally parallel, side-by-side configuration. Multiple control lines require larger clamps to secure the bundle along the length of the outer surface of the pipe string.
A method has been developed for securing control lines to a pipe string as the pipe string is made up and run into a well. U.S. Pat. No. 6,131,664 (“the '664 Patent”) is directed to using an elevated work platform constructed on the rig floor. The work platform is equipped with hydraulic tongs for making up the pipe string, and an opening above the well in the floor of the work platform that is generally aligned with the well and with an opening in the rig floor beneath the work platform. The work platform disclosed in the '664 Patent supports the spider and, when the pipe string is supported by the spider, the work platform must support the weight of entire pipe string. This requires the work platform to be built to support 200 tons or more. The work platform described in the '664 Patent also requires sufficient work area for rig personnel to use the tongs to make up joints of pipe that are lowered and aligned in position above the pipe string to be threadably made up into the pipe string.
The '664 Patent discloses that control lines are provided to the pipe string from a separate work area maintained on the rig floor and below the level of the work platform. The control lines are stored on and continuously provided from spools located lateral to the pipe string and adjacent to the opening in the rig floor. Clamps are installed by rig personnel working in the work area beneath the work platform to secure the control lines to the pipe string.
The problem with the method and apparatus for installing control lines described in the '664 Patent is that the work platform must be extremely structurally robust to support the enormous weight of the entire pipe string, the control line, the spider, and the rig personnel making up the pipe string. The erection of the work platform consumes a large amount of rig time during which no progress is made in completing the well. After the control lines and pipe string are run into the well, the work platform must be removed from the rig floor, thus consuming additional rig time. Another problem with the method and apparatus disclosed in the '664 Patent is that rig personnel working on the elevated work platform are dangerously impaired from escaping well blowout or other a well control situation.
What is needed is a method of safely securing control lines to a pipe string as the pipe string is being made up and run into a well. What is needed is a method of securing control lines to a pipe string that does not require the erection, removal or use of a special work platform for providing a work area for rig personnel that is separate from the rig floor. What is needed is a method of securing control lines to a pipe string as it is being made up and run in a well that eliminates the need for an elevated work platform strong enough to support the entire pipe string. What is needed is a method of securing control lines along the length of a pipe string as it is being made up and run in a well that eliminates obstructions to escape routes to be used by rig personnel in the event of a well blowout or other well control situation. What is needed is a method and an apparatus that enables the safe and inexpensive installation of control lines that are secured to a pipe string as it is being made up and run into a well.